Means for casting clay pipe



Feb. 22, 1938.

w, WASHO 2,109,078.

MEANS FOR CASTING CLAY PIPE Filed Dec. 4, 1935 2 Sheets-Sheet 1 [)Wezz/or MY/iam Maia Feb. 22, 1938. w. WASHO MEANS FOR CASTING CLAY PIEE Dec. 4, 1955 2 Sheets-Sheet 2 I fizzlemor 'h i/b'am Wasizo b 31 w. 77m.

lustrating the cast pipe supported on its shoulder at the spigot end.

Fig. 9 illustrates the connection joint of the two pipes, it being understood that before use the pipes are kiln dried.

Referring first to the construction of the mold this, as an assembly, is designated by the numeral 6 in which there is a lower portion |2 preferably formed with a cylindrical exterior l3, cylindrical interior surfaces i4 except for the annular ribs I5, thus they maybe considered as grooved sections I6 between the ribs. The mold is quite thick on the measurement between the inner and outer surfaces. The lower portion of the mold has an internal beveled shoulder I 8, and from the inner corner l9 of the shoulder there is an outwardly flared surface 20 terminating at the flat transverse bottom 2| of this lower portion of the mold. The upper joint surface 22 of the lower portion forms a plane surface transverse to its axis, but it has a series of recesses 23. These recesses are preferably curved on their inside and outside surfaces 24 concentric with the axis of the mold. These surfaces are also preferably tapered downwardly. The ends 25 of each recess are also tapered downwardly so that the bottom surface 25 is considerably smaller than the opening 2i at the top of each recess.

The upper removable mold section designated by the assembly numeral 30 is formed of two similar mold sections 3|. These have a lower joint surface 32 formed with a plane surface transverse to the axis of the mold, the outside surface of the assembled sections is cylindrical, as indicated at 33, forming practically a continuation of the cylinder of the lower mold section l3. The inner surface 34 is also cylindrical except for the internal ribs 35 leaving annular grooves 36, thus the interior surface for a portion of the upper section is similar to the ribbed and grooved interior lower section of the mold. A vertical joint 37 is formed between the two sections 3| of the upper portion, and this upper portion terminates in a flared upper surface 38.

The mold portion for the socket or collar of the pipe, indicated by the numeral 40, comprises a lower beveled shoulder 4|, an outwardly annular sloping surface 42, an internal shoulder 43 at the top of the surface 42 and the flared funnel surface 44. The uppersections of the mold are formed with dowels 50, these projecting downwardly from the lower joint surface 32 and being shaped to conform to the recess 23 in the lower mold section, thus the dowels have inner and outer curved surfaces concentric to the axis of the mold. As the sides and ends thus taper, they may be readily withdrawn from the recesses 23. At the vertical joints 3'! there are also complementary dowels 5| engaging in complementary recesses 52. cally tapered surfaces 53 (note Fig. 2) and a vertical inner edge 54. The upper and lower edges 55 are also tapered. The dowels and recesses are complementary, that is, one of the sections 3| has a dowel on one side and a recess at the other. This is preferable to having both recesses on the same mold'section and both vertical dowels on the opposite mold section. It will thus be seen on account of the tapers of the dowel, the upper sections of the mold may readily be removed from the lower section and separated from each other.

The procedure for casting pipe using my mold above mentioned is illustrated particularly in .Figs. 5, 6 and 7. In Fig. 5 the mold is illustrated collar or socket end 61.

These dowels have vertias supported on an imperforate board, bench, table or the like, indicated at 60. The interior of the mold is filled with a clay slurry or slip indicated at 6|. This slurry is carried above the shoulder 42 and has its surface level 62 contacting the funnel section 44. After the slurry has been left in the mold a sufficient time for absorption of water adjacent the mold, the mold is moved so as to center the mold over an opening 63 in the board or table or at the margin of the board. This allows the liquid slip to flow downwardly through the open lower end of the mold and the opening 63. This action develops a main pipe section 65 having a lower spigot end 66 and The characteristic of the spigot end is that it has a sloping shoulder 68 (note Fig. 9) which has preferably the same angle as an internal shoulder 69 formed opposite the outwardly flared surface 10, this latter being in contact with the surface 4| of the upper section of the mold. The collar has an outward sloping surface H and an inner surface 12 substantially parallel therewith. An upper beveled edge 13 is formed by the shoulder 42. The .annular grooves 74 are formed by the ribs l5 and 34 of the lower and upper mold sections. i5 is formed at the top by the sloping funnel 44 and this ring is cut away by means of a trimming knife 16 (note Fig. 7). This knife is guided around the upper part of the mold on the funnel surface 54 and forms a cut 11 in alignment with the funnel 44. The knife is then brought into more or less alignment with the inner surface 12 of the socket of the collar and forms the cut 18. This removes the remaining somewhat triangular section '79 of the ring Tl. At the bottom the trimming knife is guided on the beveled surface 20 to remove the lower ring 80, forming a cut on the line 8|, removing the lower portion of the ring. The knife is brought into alignment with the interior surface 82 of the pipe, forming a cut on the line 82 and thus removing a portion of the ring of a triangular cross-section, as indicated at 83. This leaves the lower part of the pipe, that is the spigot end, of the shape shown in Figs. 7 and 8, in which the shoulder 68 of the pipe rests on the shoulder l8 at the bottom of the mold.

When the clay pipe is sufiicientlystiffened, the upper mold sections 30 are then removed, leaving the upper part of the pipe with the collar and socket projecting above the lower mold section l2. The pipe then shrinks a sufficient The ring 7 amount in its diameter on partial drying, so that it may be lifted out of the mold. The spigot end of one pipe then is of the proper shape to interfit with the collar and socket end of an adjacent pipe, as shown in Fig. 9. Preferably a cement bonding 85 is used between the complementary shoulders 69 on the socket and 68 on the spigot and the marginal filling of cement 86 fills the space between the inside surface 12 of the collar and the lower portion of the spigot on its external surface. It will be understood, of course, before the pipes are assembled that they have been kiln dried in the usual manner. This type of casting produces a pipe which on its outside surface has the characteristic of the multiplicity til mold and the method is in the ribs on the interior of the mold for when the portion of the clay slip in contact with the mold begins to solidify by absorption of the water into the mold there would be developed a longitudinal shrinkage if the mold had a cylindrical inside surface. The ribs, however, distribute this shrinkage so that the entire weight of the solidified portion of the slip is not borne by the lower shoulders Ill of the collar portion of the mold, but each rib supports a certain proportion of the weight of the solidifying slip. After this slip has solidified to the desired extent to develop a proper thickness for the pipe, the surplus interior portion of the slip is allowed to run out through the lower portion of the mold. An additional shrinkage then develops sufficiently to allow removal of the upper section of the mold, then while the pipe is still supported in the lower part of the mold, the ribs operate to carry the proportion of the weight until the slip is dry enough and until it has shrunk in diameter in the form of a pipe so that the pipe may be lifted upwardly clear of the ribs. Manifestly, the ribs do not need to be of large dimensions, but should be quite small compared with the diameter of the pipe to be formed.

The sequence of operations, after removal of the collar or upper portion of the mold, this being done at or adjacent the casting table, is for a workman to take the lower portion of the mold with the green pipe therein to a drying room, which may be somewhat in the nature of a drying oven if desired. The pipe, while in the mold, is subjected to a sufficient temperature for a suitable length of time to both dry the lower portion of the mold and cause a further drying and shrinkage of the pipe. The workman then removes the mold with its partly dried pipe to an other portion of the drying room, or oven, removes the pipe from the mold and leaves the pipe in the drying room for more complete drying, he takes the lower portion of the mold then to the casting table for another casting operation, the mold being sufiiciently dried for this purpose. After the pipes have been sufliciently dried in the drying room or drying oven they are burnt in the kiln in the usual manner to secure a sufiicient hardness and texture of the pipe. It will be understood that if desired vitrified pipe may be made by the same process, altho it may be necessary to use a different composition in the slip from that of the softer pipes.

As a rule, the upper portion of the mold does not require to be placed in a drying room, especially when casting in summer weather, as this portion of the mold is removed from the pipe and the sections separated, exposing a large surface to the air for drying. However, if atmospheric conditions are such that the upper portion of the mold does not dry sufllciently quickly to carry on a casting operation at the desired speed, the upper portions of the mold may also be placed in a drying room.

Various changes may be made in the principles of my invention without departing from the spirit thereof as defined by the appended claims.

I claim:

1.-'In a device for casting clay pipe, a lower tubular mold formed integral having a lower internal shoulder sloping inwardly and downwardly and a lower outward flare below the shoulder to the bottom of the lower portion of the mold, an upper mold section having a transverse joint with the lower mold connected by interfitting recesses and dowels, the upper mold having a plurality of vertical joints with interconnecting recesses and dowels, the upper mold having a collar forming enlargement with a lower shoulder sloping outwardly and upwardly, an annular surface thereabove having an outward slope, an upper shoulder sloping upwardly and inwardly and having a funnel surface sloping upwardly and outwardly from the inner edge of the second shoulder, the upper and lower molds being relatively thick compared to their internal diameter and formed of a water absorbent material, the upper funnel surface being adapted to operate as a guide for a clay trimming tool at the top of the mold and the lower flared surface being adapted to act as a guide for a trimming tool at the lower part of the mold.

2. In a device for casting clay pipe, a lower tubular mold formed integral having a lower internal shoulder sloping inwardly and downwardly and a lower outward flare below the shoulder to the bottom of the lower portion of the mold, an upper mold section having a transverse joint with the lower mold and having a plurality of vertical joints, the upper mold having a collar forming enlargement and a funnel sloping upwardly and outwardly from the upper part of the collar forming enlargement, the upper and lower molds being relatively thick compared to their internal diameter and formed of a water absorbent material, the upper funnel surface being adapted to operate as a guide for a clay trimming tool and the lower flared surface being adapted to act as a guide for a trimming tool at the lower part of the mold.

3. In a device for casting clay pipe, a lower tubular mold formed integral and having a lower internal shoulder sloping inwardly and downwardly and having a lower outward flare below the shoulder to the bottom of the lower portion of the mold, an upper sectional mold having a collar forming enlargement and removable in sections from the lower mold, the upper and lower molds being relatively thick compared to their internal diameter and formed of a water absorbent material, the lower flared surface being adapted to act as a guide for a trimming tool at the lower part of the mold.

4. In a device for casting clay, a lower tubular mold formed integral and having a lower internal shoulder, an upper mold section having a transverse joint with the lower mold and a plurality of vertical joints, the upper mold having a collar forming enlargement characterized by a lower shoulder, an annular surface thereabove and an upper shoulder extending inwardly and having a funnel surface sloping upwardly and outwardly from the inner edge of the upper shoulder, the upper and lower molds being relatively thick compared to their internal diameter and formed of a water absorbent material, the upper funnel surface being adapted to operate as a guide for a clay trimming tool at the top of the mold.

WILLIAM WASHO. 

